Genetic profiles distinguish different types of hereditary ovarian cancer

Abstract

Heredity represents the strongest risk factor for ovarian cancer with disease predisposing mutations identified in 15% of the tumors. With the aim to identify genetic classifiers for hereditary ovarian cancer, we profiled hereditary ovarian cancers linked to the hereditary breast and ovarian cancer (HBOC) syndrome and the hereditary non-polyposis colorectal cancer (HNPCC) syndrome. Genome-wide array comparative genomic hybridization was applied to 12 HBOC associated tumors with BRCA1 mutations and 8 HNPCC associated tumors with mismatch repair gene mutations with 24 sporadic ovarian cancers as a control group. Unsupervised cluster analysis identified two distinct subgroups related to genetic complexity. Sporadic and HBOC associated tumors had complex genetic profiles with an average 41% of the genome altered, whereas the mismatch repair defective tumors had stable genetic profiles, with an average 18% of the genome altered. Losses of 4q34, 13q12-q32 and 19p13 were overrepresented in the HBOC subset. Discriminating genes within these regions include BRCA2, FOXO1A and RB1. Gains on chromosomes 17 and 19 characterized the HNPCC tumors, but target genes herein are unknown. The results indicate that HBOC and HNPCC associated ovarian cancer develop along distinct genetic pathways and genetic profiles can thus be applied to distinguish between different types of hereditary ovarian cancer.